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Use NVSwitch on GPU Server

After creating a GPU Server, you can enable the NVSwitch feature on the GPU Server’s VM (Guest OS) and use fast GPU-to-GPU P2P communication.

Caution
Only the GPU Server (8 GPU) and Multi-node GPU Cluster of Samsung Cloud Platform are connected with NVSwitch and NVLink.

Exploring NVIDIA NVSwitch for Multi GPU

NVLink expands I/O by directly connecting multiple GPUs within a server both bidirectionally and GPU-to-GPU. Using NVSwitch, you can connect all GPUs in a server with full NVLink bandwidth.

Checking NVSwitch operation

Check the NVIDIA Fabric Manager, NVIDIA NVLink topology, and NVIDIA NVLink Status on the GPU server.

Reference
The example for checking NVSwitch operation is explained using the A100 GPU Server (g1v128a8) as a reference.

NVIDIA Fabric Manager operating status

Verify that active (running) is displayed when operating normally.

~$ systemctl status nvidia-fabricmanager
Color mode
nvidia-fabricmanager.service - NVIDIA fabric manager service
     Loaded: loaded (/lib/systemd/system/nvidia-fabricmanager.service; enabled; vendor preset: enabled)
     Active: active (running) since Mon 2026-02-02 16:23:27 KST; 32min ago
   Main PID: 2191 (nv-fabricmanage)
      Tasks: 18 (limit: 629145)
     Memory: 18.0M
        CPU: 33.461s
     CGroup: /system.slice/nvidia-fabricmanager.service
             └─2191 /usr/bin/nv-fabricmanager -c /usr/share/nvidia/nvswitch/fabricmanager.cfg
nvidia-fabricmanager.service - NVIDIA fabric manager service
     Loaded: loaded (/lib/systemd/system/nvidia-fabricmanager.service; enabled; vendor preset: enabled)
     Active: active (running) since Mon 2026-02-02 16:23:27 KST; 32min ago
   Main PID: 2191 (nv-fabricmanage)
      Tasks: 18 (limit: 629145)
     Memory: 18.0M
        CPU: 33.461s
     CGroup: /system.slice/nvidia-fabricmanager.service
             └─2191 /usr/bin/nv-fabricmanager -c /usr/share/nvidia/nvswitch/fabricmanager.cfg
Code block. Check NVIDIA Fabric Manager status

Check NVIDIA NVLink topology

Check the NVIDIA NVLink topology.

~$ nvidia-smi topo -m
Color mode
nvidia-smi topo -m
        GPU0    GPU1    GPU2    GPU3    GPU4    GPU5    GPU6    GPU7    CPU Affinity    NUMA Affinity   GPU NUMA ID
GPU0     X      NV12    NV12    NV12    NV12    NV12    NV12    NV12    0-127   0-7             N/A
GPU1    NV12     X      NV12    NV12    NV12    NV12    NV12    NV12    0-127   0-7             N/A
GPU2    NV12    NV12     X      NV12    NV12    NV12    NV12    NV12    0-127   0-7             N/A
GPU3    NV12    NV12    NV12     X      NV12    NV12    NV12    NV12    0-127   0-7             N/A
GPU4    NV12    NV12    NV12    NV12     X      NV12    NV12    NV12    0-127   0-7             N/A
GPU5    NV12    NV12    NV12    NV12    NV12     X      NV12    NV12    0-127   0-7             N/A
GPU6    NV12    NV12    NV12    NV12    NV12    NV12     X      NV12    0-127   0-7             N/A
GPU7    NV12    NV12    NV12    NV12    NV12    NV12    NV12     X      0-127   0-7             N/A

Legend:

  X    = Self
  SYS  = Connection traversing PCIe as well as the SMP interconnect between NUMA nodes (e.g., QPI/UPI)
  NODE = Connection traversing PCIe as well as the interconnect between PCIe Host Bridges within a NUMA node
  PHB  = Connection traversing PCIe as well as a PCIe Host Bridge (typically the CPU)
  PXB  = Connection traversing multiple PCIe bridges (without traversing the PCIe Host Bridge)
  PIX  = Connection traversing at most a single PCIe bridge
  NV#  = Connection traversing a bonded set of # NVLinks
nvidia-smi topo -m
        GPU0    GPU1    GPU2    GPU3    GPU4    GPU5    GPU6    GPU7    CPU Affinity    NUMA Affinity   GPU NUMA ID
GPU0     X      NV12    NV12    NV12    NV12    NV12    NV12    NV12    0-127   0-7             N/A
GPU1    NV12     X      NV12    NV12    NV12    NV12    NV12    NV12    0-127   0-7             N/A
GPU2    NV12    NV12     X      NV12    NV12    NV12    NV12    NV12    0-127   0-7             N/A
GPU3    NV12    NV12    NV12     X      NV12    NV12    NV12    NV12    0-127   0-7             N/A
GPU4    NV12    NV12    NV12    NV12     X      NV12    NV12    NV12    0-127   0-7             N/A
GPU5    NV12    NV12    NV12    NV12    NV12     X      NV12    NV12    0-127   0-7             N/A
GPU6    NV12    NV12    NV12    NV12    NV12    NV12     X      NV12    0-127   0-7             N/A
GPU7    NV12    NV12    NV12    NV12    NV12    NV12    NV12     X      0-127   0-7             N/A

Legend:

  X    = Self
  SYS  = Connection traversing PCIe as well as the SMP interconnect between NUMA nodes (e.g., QPI/UPI)
  NODE = Connection traversing PCIe as well as the interconnect between PCIe Host Bridges within a NUMA node
  PHB  = Connection traversing PCIe as well as a PCIe Host Bridge (typically the CPU)
  PXB  = Connection traversing multiple PCIe bridges (without traversing the PCIe Host Bridge)
  PIX  = Connection traversing at most a single PCIe bridge
  NV#  = Connection traversing a bonded set of # NVLinks
Code block. Check NVIDIA NVLink topology

Check NVIDIA NVLink Status

Check the NVIDIA NVLink Status.

~$ nvidia-smi topo -m
Color mode
GPU 1: NVIDIA A100-SXM4-80GB (UUID: GPU-64a2f685-bb12-c4af-105c-0726ece9c8d7)
         Link 0: 25 GB/s
         Link 1: 25 GB/s
         Link 2: 25 GB/s
         Link 3: 25 GB/s
         Link 4: 25 GB/s
         Link 5: 25 GB/s
         Link 6: 25 GB/s
         Link 7: 25 GB/s
         Link 8: 25 GB/s
         Link 9: 25 GB/s
         Link 10: 25 GB/s
         Link 11: 25 GB/s
GPU 2: NVIDIA A100-SXM4-80GB (UUID: GPU-2269851b-71cd-f6c7-50c5-ba1525cf3ce8)
         Link 0: 25 GB/s
         Link 1: 25 GB/s
         Link 2: 25 GB/s
         Link 3: 25 GB/s
         Link 4: 25 GB/s
         Link 5: 25 GB/s
         Link 6: 25 GB/s
         Link 7: 25 GB/s
         Link 8: 25 GB/s
         Link 9: 25 GB/s
         Link 10: 25 GB/s
         Link 11: 25 GB/s
GPU 3: NVIDIA A100-SXM4-80GB (UUID: GPU-4c397bbf-95fc-5c29-918a-a429cbe45a7a)
         Link 0: 25 GB/s
         Link 1: 25 GB/s
         Link 2: 25 GB/s
         Link 3: 25 GB/s
         Link 4: 25 GB/s
         Link 5: 25 GB/s
         Link 6: 25 GB/s
         Link 7: 25 GB/s
         Link 8: 25 GB/s
         Link 9: 25 GB/s
         Link 10: 25 GB/s
         Link 11: 25 GB/s
GPU 4: NVIDIA A100-SXM4-80GB (UUID: GPU-0e350204-9fb6-2cbe-538e-8f7849658eb8)
         Link 0: 25 GB/s
         Link 1: 25 GB/s
         Link 2: 25 GB/s
         Link 3: 25 GB/s
         Link 4: 25 GB/s
         Link 5: 25 GB/s
         Link 6: 25 GB/s
         Link 7: 25 GB/s
         Link 8: 25 GB/s
         Link 9: 25 GB/s
         Link 10: 25 GB/s
         Link 11: 25 GB/s
GPU 5: NVIDIA A100-SXM4-80GB (UUID: GPU-45f0c453-4760-edd4-3af9-25c5ea7473a5)
         Link 0: 25 GB/s
         Link 1: 25 GB/s
         Link 2: 25 GB/s
         Link 3: 25 GB/s
         Link 4: 25 GB/s
         Link 5: 25 GB/s
         Link 6: 25 GB/s
         Link 7: 25 GB/s
         Link 8: 25 GB/s
         Link 9: 25 GB/s
         Link 10: 25 GB/s
         Link 11: 25 GB/s
GPU 6: NVIDIA A100-SXM4-80GB (UUID: GPU-38409794-bb34-430e-3c50-90b42cb2bb72)
         Link 0: 25 GB/s
         Link 1: 25 GB/s
         Link 2: 25 GB/s
         Link 3: 25 GB/s
         Link 4: 25 GB/s
         Link 5: 25 GB/s
         Link 6: 25 GB/s
         Link 7: 25 GB/s
         Link 8: 25 GB/s
         Link 9: 25 GB/s
         Link 10: 25 GB/s
         Link 11: 25 GB/s
GPU 7: NVIDIA A100-SXM4-80GB (UUID: GPU-3fb478aa-801b-eb64-55c2-0ffc3f2ce404)
         Link 0: 25 GB/s
         Link 1: 25 GB/s
         Link 2: 25 GB/s
         Link 3: 25 GB/s
         Link 4: 25 GB/s
         Link 5: 25 GB/s
         Link 6: 25 GB/s
         Link 7: 25 GB/s
         Link 8: 25 GB/s
         Link 9: 25 GB/s
         Link 10: 25 GB/s
         Link 11: 25 GB/s
GPU 1: NVIDIA A100-SXM4-80GB (UUID: GPU-64a2f685-bb12-c4af-105c-0726ece9c8d7)
         Link 0: 25 GB/s
         Link 1: 25 GB/s
         Link 2: 25 GB/s
         Link 3: 25 GB/s
         Link 4: 25 GB/s
         Link 5: 25 GB/s
         Link 6: 25 GB/s
         Link 7: 25 GB/s
         Link 8: 25 GB/s
         Link 9: 25 GB/s
         Link 10: 25 GB/s
         Link 11: 25 GB/s
GPU 2: NVIDIA A100-SXM4-80GB (UUID: GPU-2269851b-71cd-f6c7-50c5-ba1525cf3ce8)
         Link 0: 25 GB/s
         Link 1: 25 GB/s
         Link 2: 25 GB/s
         Link 3: 25 GB/s
         Link 4: 25 GB/s
         Link 5: 25 GB/s
         Link 6: 25 GB/s
         Link 7: 25 GB/s
         Link 8: 25 GB/s
         Link 9: 25 GB/s
         Link 10: 25 GB/s
         Link 11: 25 GB/s
GPU 3: NVIDIA A100-SXM4-80GB (UUID: GPU-4c397bbf-95fc-5c29-918a-a429cbe45a7a)
         Link 0: 25 GB/s
         Link 1: 25 GB/s
         Link 2: 25 GB/s
         Link 3: 25 GB/s
         Link 4: 25 GB/s
         Link 5: 25 GB/s
         Link 6: 25 GB/s
         Link 7: 25 GB/s
         Link 8: 25 GB/s
         Link 9: 25 GB/s
         Link 10: 25 GB/s
         Link 11: 25 GB/s
GPU 4: NVIDIA A100-SXM4-80GB (UUID: GPU-0e350204-9fb6-2cbe-538e-8f7849658eb8)
         Link 0: 25 GB/s
         Link 1: 25 GB/s
         Link 2: 25 GB/s
         Link 3: 25 GB/s
         Link 4: 25 GB/s
         Link 5: 25 GB/s
         Link 6: 25 GB/s
         Link 7: 25 GB/s
         Link 8: 25 GB/s
         Link 9: 25 GB/s
         Link 10: 25 GB/s
         Link 11: 25 GB/s
GPU 5: NVIDIA A100-SXM4-80GB (UUID: GPU-45f0c453-4760-edd4-3af9-25c5ea7473a5)
         Link 0: 25 GB/s
         Link 1: 25 GB/s
         Link 2: 25 GB/s
         Link 3: 25 GB/s
         Link 4: 25 GB/s
         Link 5: 25 GB/s
         Link 6: 25 GB/s
         Link 7: 25 GB/s
         Link 8: 25 GB/s
         Link 9: 25 GB/s
         Link 10: 25 GB/s
         Link 11: 25 GB/s
GPU 6: NVIDIA A100-SXM4-80GB (UUID: GPU-38409794-bb34-430e-3c50-90b42cb2bb72)
         Link 0: 25 GB/s
         Link 1: 25 GB/s
         Link 2: 25 GB/s
         Link 3: 25 GB/s
         Link 4: 25 GB/s
         Link 5: 25 GB/s
         Link 6: 25 GB/s
         Link 7: 25 GB/s
         Link 8: 25 GB/s
         Link 9: 25 GB/s
         Link 10: 25 GB/s
         Link 11: 25 GB/s
GPU 7: NVIDIA A100-SXM4-80GB (UUID: GPU-3fb478aa-801b-eb64-55c2-0ffc3f2ce404)
         Link 0: 25 GB/s
         Link 1: 25 GB/s
         Link 2: 25 GB/s
         Link 3: 25 GB/s
         Link 4: 25 GB/s
         Link 5: 25 GB/s
         Link 6: 25 GB/s
         Link 7: 25 GB/s
         Link 8: 25 GB/s
         Link 9: 25 GB/s
         Link 10: 25 GB/s
         Link 11: 25 GB/s
Code block. Check NVIDIA NVLink status
Use Multi-instance GPU on GPU Server
Install ServiceWatch Agent